Heretofore, there has been known a filling packaging apparatus (hereinafter referred to simply as “packaging apparatus”) for continuously producing packaged products (package bags) filled with content such as a liquid, a viscous substance, or the like, for example. Generally, the packaging apparatus manufactures package bags by folding a film in the form of an elongate sheet reeled out from a film roll, into a tubular form, and feeding the content into the film and forming sealed regions on the film.
FIG. 1 shows a film reeled out from a film roll. As shown in FIG. 1A, end marks A are normally applied in advance to a terminal end portion of the film that is wound on the film roll for indicating the end of the film. End marks A are regions where aluminum foil tapes or vinyl tapes are applied, for example. The packaging apparatus uses an optical sensor or the like for detecting these marks to stop the packaging operation. The film also has, in addition to end marks A, a plurality of registration marks C disposed at a given pitch which is established depending on the size (lengthwise dimension) of package bags to be manufactured.
Actually, the film that is wound on film roll R comprises a plurality of joined films of a predetermined length. As shown in FIG. 1B, the films are joined to each other by tape B′ across seam joint B. Tape B′ itself is not thermally sealable. If an attempt is made to thermally seal table B′, then the tape will be melted, causing problems.
JP11-236002A discloses a packaging apparatus which does not thermally seal seam joint B between tapes. The disclosed packaging apparatus will be briefly described below with reference to FIG. 2.
As shown in FIG. 2, the packaging apparatus disclosed in JP11-236002A is of a general structure which comprises folding guide 114 for folding a film into two plies, vertical sealing mechanism 130 for forming vertical seal F1 on the folded sheet, feeding nozzle 15 for feeding a content into the film, horizontal sealing mechanism 150 for forming horizontal seals F2 on the folded sheet at portions which will serve as bottom and top regions of a package bag, and cutting mechanism 160 for cutting horizontal seals F2 to sever the package bag from the film. These mechanisms are actuated at given timings in timed relation to the feeding of the film to successively manufacture package bags filled with the content.
The packaging apparatus is mainly characterized in that it further includes seam joint detecting means 16 for detecting seam joints B, and the actuation of the above mechanisms is controlled based on the detected result from seam joint detecting means 16 to prevent tapes B′ at seam joints B from being thermally sealed. Therefore, the problems (e.g., a portion of the melted tape is applied to a seal bar of the horizontal sealing mechanism which results in lowering the quality of package bags which will subsequently be manufactured) caused by the melted tape are prevented from arising.
Another known packaging apparatus of this type includes a mechanism for joining the terminal end of a film from a film roll and the beginning end of the next film roll to each other at the time that the first-mentioned film roll is finished up (see JP09-58616A). The joining mechanism allows the packaging apparatus to continuously manufacture package bags without the need for a tedious process for setting a next film roll in place again each time one film roll is used up.